Apparatus for forming the teeth of bevel gears



F. M. LEWIS, APPARATUS FOR FORMING THE TEETII OF BEVEL GEARS. APPLICATION FILED N0V.29, I92I.

1 ,41 2,3 1 1 Patented Apr. 11, 1922.

4 SHEETS-SHEETI.

III/v ezvbaza 7. 117 17 11225 F. M. LEWIS. APPARATUS FOR FORMING THE TEETH 0F BEVEL GEARS. APPLICATION FILED NOV-29, 1921.

1,412,31 1, Patented Apr. 11, 1922.

4 $HEETS-SHEET 2- F. M. LEWIS. APPARATUS FOR FOR MINGTHE TEETH 0F BEVEL GEARS. APPLICATION FILED NOV.29.1921. 1,412,311. Patented Apr- 11, 1922.

4 SHEETS-SHEET 3- F- M. LEWIS.

APPARATUS FOR FORMING THE TEETH 0F BEVE L GEARS. APPLICATION FlLED NOV. 29. 192] 1 ,412;31 1, Patented Apr. 11, 1922.

UNITED STATES PATENT OFFICE.

FRANK MICHAEL LEWIS, OF P IMLICO. LONDON, ENGLAND, ASSIGNORv OF ONE-HALF TO B. S. A. TOOLS, LEMITED. OF BIRMINGHAM, ENGLAND.

APPARATUS FOR FORMING THE TEE-TH OF BEVEL GEARS.

Application filed November 29, 1921.

To all whom it may concern:

Be it known that I. FRANK MioHAn-L Lewis, a subject of the King of Great Britain and Ireland, and residing at 16, Lupus Street, Pimlico, London,S. WV. 1. England, have invented certain new and useful I1n proved Apparatus for Forming the Teeth of Bevel Gears, (for which I have filed an application in Great Britain May 27, 1920, #14,482,) of which the following is a specification.

This invention relates to apparatus for generating the teeth of bevel toothed gears.

In such apparatus it is necessary that the blank and cutter should have a relative combined rotary movement and rolling movement about the centre of a cone and the ratio of the speeds of rotary and rolling movements has to be varied for bevel wheelsot varying pitch cones. This usually accomplished by the use of different trains of gears giving difl'erent speed ratios, such gear trains being subject to the usual drawbacks attendant upon their practicaloperation and increasing the complexity of the machine.

The object of the present invention is to devise a simple and efiicient form of machine which may be readily and rapidly adjusted for gears of different pitch cones and dimensions without necessitating the use of any trains of change speed gear.

The invention consists in apparatus of the above character in which two rectilinear movements adjustable in relation to one another are obtained, one being a conversion from a rotary movement and the other being converted into a rotary movement.

The invention also consists in apparatus of the above character in which the rectilinear movements are adjusted in'relation' to one another by the use of a'lever with adjustable fulcrum.

The invention further consists in the apparatus and details in connection therewith hereinafter described or indicated.

The accompanying drawings illustrate two modes of carrying out my invention.

.Figure' 1 is a side elevation of one convenient form of apparatus in accordance with the invention. 1

Figure 2 is a front elevation, and

Figure 8 is a plan.

. Figure 4 is a transve se ec ional e evation Specification of Letters Patent.

Patented Apr. 11, 1922.

Serial No. 518,712.

showing a modified form of apparatus in accordance with the invention.

Figure 5 is a longitudinal sectional elevatlon.

Figure 6 is a plan, and

Figure 7 is a plan with the upper part or" the apparatus removed.

In carrying my invention into effect in one convenient manner as illustrated, for example, in Figures 1 to 3, I provide-the machine or attachment with a worm wheel a rigidly secured to the base Z) in any suitable manner as, for example, by means of the stud 0.

The worm wheel a gears with feed worm (Z which is rotated first in one direction and then in the other by suitable means and is carried in bearings mounted upon a plate e rotatable about the axis of the fixed worm wheel a so that rotation of the worm (Z in the two directions causes the plate 6 carrying the sameto be given an angular oscillatory movement about the centre of the worm wheel a. The feed worm (Z also engages with a haltnut 7 secured to a slide 5/ upon the plate 6, which slide is therefore given a rectilinear movement obtained by conversion of the rotary 'movement of the feed worm through the intermediary of the half nut or other like member engaging therewith.

The slide 9 is connected by means of a transverse member 72 carried by the member 71 pivoted upon the plate a, to a second slide is which carries a worm Z (which may for convenience be termed the rack indexing worm) adapted to gear with the worm wheel on mounted in bearings it carried by the angularly movable plate 0 and upon the end of the spindle or mandril on which the work blank 0 is mounted so that the rectilinear movement of the rack indexing worm will be converted (by a rack and pinion action) into rotary movement of its worm wheel and therefore of the blank 0.

The transverse member h connecting the slides (7 and 7a through the intermediary of its angular rolling movement, a suitable scale on the lever 29 and Vernier g or other setting or adjusting means being provided if necessary or desirable in conjunction with the transverse slide or member ii.

Indexing ofthe blank may be effected by any suitable indexing means (not shown in Figures 1 to 3 but indicated at r in Figures 6 and 7) arranged to act upon the rack indexing worm Z, and the means fordriving the feed worm (Z may either be carried upon the angularly movable plate or framework 6 or may be mounted separately and connected with the feed worm by telescopic and universally movable transmission meclr anism.

In a convenient practical. embodiment th drive may be eltected by a reversible electric motor (not shown) the reversal of which is effected by switches adapted to be actuated by suitable means at each end of the movement of the apparatus.

The foregoing arrangement is a very convenient embodiment of the invention in that it enables the cutter (shown dotted at s) to be arranged at the upper side of the blank but with suitable modifications the cutter may be arranged at any other convenient part in relation to the blank, it being understood that the cutter may be of the rotary kind when forming arcuate teeth or may be of any other suitable form depending upon the form of gear teeth to be generated and that while it is so illustrated in Figure 1 it is not necessary that the cutter should intersect the apex of the pitch cone of the blank.

For obtaining the correct tooth thickness I may suitably adjust the index point in relation to which the indexing member is set.

When forming arcuate teeth the generation is preferably eiiected from the base cone and the two flanks of the teeth are cut to the same radius but with other forms of teeth it may be desirable to generate from the pitch cone.

Figures 4 to 7 illustrate a modification of the invention which in its main teaturesot construction is similar to that hereinbefore described, as will be apparent from the fore going description and from the fact that similar letters oi reference are used todenote similar parts in the two constructions.

In this form of apparatus, however, the upper part 25 of the apparatus carrying the bearings a for the blank spindle is made slidable in order that the amount of overhang of the spindle may be varied according to variations in the size 01": blank being operated upon.

Furthermore, the spindle is provided with a nut u adapted to take up end play of the spindle following on adjustment of the position of the part 2?, and having a pin extension 11, adapted to engage a tork e fixed to the sleeve on which tie wormwheel m is carried. and provided with sore-vs angular adjustment of the blank for in the desired tooth thickness.

lidoreover, the transverse member 7; connected to the slides g is by means or rod-like members w having a certain amount of rotary as :well as lateral movement in the members 20 '(which are rotatable relative to the slides g is) and pivoted to the lever 32 by means oi the pins w fixed thereon so that the connection between thevmember h and the slides g permits of a limited amountotuniversal movement, thus obviating any risk of the parts becoming jammed during the operation of the apparatus.

The foregoing details of construction are c for obtamgiven by way of example only in order to 7 illustrate the nature of the invention and the manner in which it may be carried into ei'i'ect in practice, and it will be understood that the invention is not to be limited to such details as they may bemodified both as to their form and arrangement and the manner in which they co-operate with one another toproducc the required variation in speed ratio without the use 01": trains of gears -all as may be determined by the form of gear to be cut or any particular practical requirements that may have to be fulfilled. For example, other methods may be employed for obtaining the required rectilinear movements as, for example, the'feed member (Z (which may be either a rack or a worm) may itself be adapted to slide and be con nected direct to the transverse member connected to the second slide. In this case, the plate or frame 0 must bysuitable means be caused to oscillate about the centre of a. If a worm be used instead of a rack for this purpose it offers a convenient means of adjusting the machine when setting up by enabling the plate or frame 0 to be adjusted relatively to the base.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. Apparatus for generating the teeth of bevel toothed gears comprising members mounted for rectilinear movement, means connecting said members and permitting adjustment of the relative movement thereof, rotary actuating means imparting rectilinear movement to one of said members, and means'for converting the rectilinear movement of the other member into rotary movement. I

2. Apparatus for generating the teeth of bevel toothed gears comprising members mounted for rectilinear movement, a lever arranged to transmit the movement of one member to the other member, an adjustable fulcrum for said lever for varying the relative movement of the members, rotary actuating means imparting rectilinear movement to one of said members, and means for converting the rectilinear movement of the other member into rotary movement.

3. Apparatus for generating the teeth of bevel toothed gears comprising members mounted for rectilinear movement, a lever having an adjustable fulcrum connecting said members whereby the relative movement thereof may be varied, said members being connected With said lever for limited universal movement, rotary actuating means impartin rectilinear movement to one of said mem ers, and means for converting the rectilinear movement of the other member into rotary movement.

4. Apparatus for generating the teeth of bevel toothed gears comprising in combination a fixed worm wheel, a feed worm cooperating therewith and mounted upon a plate rotatable about the centre of the worm wheel, a slide movable rectilinearly by said feed worm and a variable lever connecting said slide with a second slide carrying a Worm adapted to co-operate with a Worm wheel mounted upon the spindle carrying the blank, substantially as described.

5. Apparatus as claimed. in claim 4 in which indexing is effected upon that Worm which co-operates with the worm wheel rotating the blank, substantially as described.

6. In apparatus according to claim 3, the provision of means for adjusting for Varying the thickness of tooth, substantially as described.

7. Apparatus as claimed in claim 3, in Which a scale and vernier or the like is provided in conjunction with the Variable lever, substantially as described.

8. In an apparatus according to claim a, the provision of adjusting means -for varying the thickness of the tooth.

In testimony whereof I have signed my name to this specification.

FRANK MICHAEL LEWIS. 

